Hydrokinetic torque coupling device for a motor vehicle

ABSTRACT

The invention relates to a hydrokinetic torque coupling device for a motor vehicle, comprising a torque input element ( 11 ) intended to be coupled to a crankshaft ( 1 ), an impeller wheel ( 3 ) rotationally coupled to the torque input element ( 11 ) and able to hydrokinetically drive a turbine wheel ( 4 ) through a reactor ( 5 ), a torque output element ( 8 ) intended to be coupled to a transmission input shaft ( 2 ), clutch means ( 10 ) able to rotationally couple the torque input element ( 11 ) and the torque output element ( 8 ) in an engaged position, through damping means ( 21, 25 ) and able to rotationally uncouple the torque input element ( 11 ) and the torque output element ( 8 ) in a disengaged position.

FIELD OF THE INVENTION

The present invention relates to a hydrokinetic torque coupling devicefor a motor vehicle, such as a torque converter, for instance.

BACKGROUND OF THE INVENTION

A known hydrodynamic torque converter is schematically and partiallyillustrated in FIG. 1 and makes it possible to transmit a torque fromthe output shaft of an internal combustion engine in a motor vehicle,such as for instance a crankshaft 1, to a transmission input shaft 2.

The torque converter conventionally comprises an impeller wheel 3, ableto hydrokinetically drive a turbine wheel 4 through a reactor 5.

The impeller wheel 3 is coupled to the crankshaft 1 and the turbinewheel 4 is coupled to guiding washers 6.

A first group of elastic members 7 a, 7 b of the compression spring typeis mounted between the guiding washers 6 and a central hub 8 coupled tothe transmission input shaft 2. The elastic members 7 a, 7 b of thefirst group are arranged in series through a phasing member 9, so thatsaid elastic members 7 a, 7 b are deformed in phase with each other,with said phasing member 9 being movable relative to the guiding washers6 and relative to the hub 8.

A second group of elastic members 7 c is mounted with some clearancebetween the guiding washers 6 and the central hub 8 in parallel with thefirst group of elastic members 7 a, 7 b, with said elastic members 7 cbeing adapted to be active on a limited angular range, more particularlyat the end of the angular travel of the guiding washers 6 relative tothe central hub 8. The angular travel, or an angular shift α, of theguiding washers 6 relative to the hub 8, is defined relative to a restposition (α=0) wherein no torque is transmitted through damping meansformed by the above-mentioned elastic members 7 a, 7 b.

The torque converter further comprises clutch means 10 adapted totransmit a torque from the crankshaft 1 to the guiding washers 6 in adetermined operation phase, without any action from the impeller wheel 3and the turbine wheel 4.

The second group of elastic members 7 c makes it possible to increasethe stiffness of the damping means at the end of the angular travel,i.e. for a significant a angular offset of the guiding washers 6relative to the hub 8 (or vice versa).

It can be seen that the representation of function M=f(α) which definesthe M torque transmitted through the device according to the α angularshift, comprises a first linear portion of slope Ka (for the low valuesof the α angular shift) and a second, more important, linear portion ofslope Kb (for the high value of the α angular shift). Ka and Kb are theangular stiffness of the device, at the beginning and at the end of theangular travel respectively. If K1 defines the cumulated stiffness ofthe first springs of each pair of the first group, and K2 defines thecumulated stiffness of the second springs of each pair of the firstgroup, and K3 defines the cumulated stiffness of the springs of thesecond group, then Ka=(K1·K2)/(K1+K2) and Kb=Ka+K3.

The break of slope between the first and second portions of the curvemay generate vibrations and a significant hysteresis upon operation ofthe torque converter which might affect the quality of filtrationobtained using the damping means.

SUMMARY OF THE INVENTION

The invention more particularly aims at providing a simple, efficientand cost-effective solution to this problem.

For this purpose, it provides a hydrokinetic torque coupling device fora motor vehicle comprising a torque input element intended to be coupledto a crankshaft, a turbine wheel, an impeller wheel rotationally coupledto the torque input element and able to hydrokinetically drive theturbine wheel, a torque output element intended to be coupled to atransmission input shaft, damping means, clutch means adapted torotationally couple the torque input element and the torque outputelement in an engaged position, through the damping means, and able torotationally uncouple the torque input element and the torque outputelement in a disengaged position, with the damping means being adaptedto act against the rotation of the torque input element relative to thetorque output element, in the engaged position of the clutch means, withthe damping means comprising at least one elastic blade which rotatestogether with the torque output element or the clutch meansrespectively, and a supporting member carried by the clutch means or thetorque output element respectively, with the blade being elasticallymaintained supported by said supporting member, with said elastic bladebeing adapted to bend upon rotation of the torque input element relativeto the torque output element, in an engaged position, with thesupporting means or the elastic blade respectively being mounted on atleast one supporting flange being so mounted as to pivot on the torqueoutput element through a rolling bearing such as a ball bearing, forinstance.

Such damping means give a characteristic gradual curve, without anybreak of slope. The invention thus makes it possible to reduce thevibrations generated in operation and provides a high quality offiltration.

Besides, such a hydrokinetic torque coupling device is easy to mount andrather inexpensive.

It should be noted that the words “radial” and “axial” are defined withrespect to the hydrokinetic torque coupling device, which is the axis ofrotation of the impeller wheel or of the turbine wheel.

It should be noted that a hydrokinetic torque coupling device may be atorque converter when the hydrokinetic torque coupling means comprise animpeller wheel, a turbine wheel and a reactor, or may be a hydrokineticcoupling device when the hydrokinetic torque coupling means have noreactor.

Mounting the supporting flange on the central hub through a bearingprovides a frictionless guiding which ensures a frictionless relativerotation while enabling the stresses to be taken over.

The supporting flange may comprise a radially internal part mountedabout the torque output element through the bearing, and a radiallyexternal part whereon the supporting member is mounted, with theradially internal and external parts being fastened together, by rivets,for instance.

According to one embodiment, the radially internal part of thesupporting flange may comprise a cylindrical rim surrounding thebearing.

In another embodiment, the radially internal part of the supportingflange may comprise a shoulder delimiting a cylindrical surfaceextending at one end into a radial surface, with the bearing beingaccommodated in said shoulder and adapted to rest on the radial surfaceof said shoulder.

The hydrokinetic torque coupling device may comprise at least oneinternal flange which rotates together with the torque output elementand at least one radially external flange positioned radially at leastpartially outside the internal flange, and pivoting relative to theinternal flange, with the elastic blade rotating together with theinternal flange, respectively the external flange, with the supportingmember being connected to the external flange, respectively the internalflange.

Besides, the hydrokinetic torque coupling device may comprise tworadially internal flanges rotating together with the torque outputelement and two radially external flanges so mounted as to pivot aboutsaid internal flanges, with the elastic blade being mounted in a spaceaxially arranged between the internal flanges and/or between theexternal flanges, with the supporting member being mounted in a spaceaxially arranged between the external flanges, respectively the internalflanges, with one of the external flanges being formed by the supportingflange.

The turbine wheel may be rotationally coupled to the torque outputelement and to the internal flange.

The clutch means may comprise at least one piston rotationally coupledto the supporting flange, with the piston being able to move between anengaged position wherein it is rotationally coupled to the torque inputelement and a disengaged position wherein it is rotationally uncoupledfrom the torque input element.

The torque output element then comprises a radial surface, with themotion of the piston in the engaged position being limited by the pistonresting on said radial surface of the torque output element.

Besides, the torque output element may comprise a central hub.

The bearing may be a rolling bearing or a ring, for instance a guidingring made of plastic or bronze, or more generally a ring having a lowcoefficient of friction comprising a non-stick coating. Such a ring maybe mounted, through a friction-type connection, on the supporting flangeor on the torque output element.

Besides, the hydrokinetic torque coupling device may comprise a reactor,with the impeller wheel being adapted to hydrokinetically drive theturbine wheel through the reactor. The hydrokinetic torque couplingdevice thus forms a hydrodynamic torque converter.

The hydrokinetic torque coupling device may also comprise one or more ofthe following characteristics:

-   -   the supporting member comprises at least one rolling body, such        as a roller so mounted as to pivot about a shaft, for instance        through a rolling bearing, such as a needle bearing, for        instance.    -   the supporting member is mounted on the radially external        periphery of the supporting flange,    -   the impeller wheel is rotationally coupled to a cover wherein        the impeller wheel, the turbine wheel, the reactor and/or the        damping means are at least partially accommodated.    -   the torque input element comprises said cover,    -   the elastic blade is so designed that, in the engaged position,        in a relative angular position between the torque input element        and the torque output element different from a rest position,        the supporting member exerts a bending stress on the elastic        blade causing a cross reaction force of the elastic blade on the        supporting member, with such reaction force having a        circumferential component which tends to move back the torque        input element and the torque output element toward said relative        rest position.    -   the elastic blade is so designed that, in the engaged position,        in a relative angular position between the torque input element        and the torque output element different from a rest position,        the supporting member exerts a bending stress on the elastic        blade causing a cross reaction force of the elastic blade on the        supporting member, with such reaction force having a        circumferential component which tends to move back the torque        input element and the torque output element toward said relative        rest position.    -   in the engaged position, the angular displacement of the torque        input element relative to the torque output element is greater        than 20° and preferably greater than 40°.    -   the elastic blade comprises a fastening portion and an elastic        portion comprising a radially internal strand, a radially        external strand and a bowed or bent portion connecting the        internal 31 a and the external strand.    -   the damping means comprise at least two elastic leaves, with        each elastic blade rotating together with the torque output        element, or the torque input element in engaged position        respectively, with each blade being associated with a supporting        element rotationally linked with the torque input element in        engaged position, or the torque output element respectively,        with each blade being elastically maintained supported by said        matching supporting element, with each elastic blade being        adapted to bend upon rotation of the torque input element        relative to the torque output element in engaged position.    -   the impeller wheel is rotationally coupled to the torque input        element and is adapted to hydrokinetically drive the turbine        wheel, through a reactor.    -   the turbine wheel and the flange are rotationally connected to        the central hub by a common fastening means or are each        rotationally connected to the central hub by a different        fastening means.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood, and other details,characteristics and advantages of the invention will appear upon readingthe following description given by way of a non restrictive examplewhile referring to the appended drawings wherein:

FIG. 1 is a schematic representation of a torque converter of the priorart,

FIG. 2 is a sectional view along an axial plane, of a torque converteraccording to a first embodiment of the invention,

FIG. 3 is a sectional front view illustrating a supporting member and anelastic blade of a torque converter according to the invention,

FIG. 4 is a view corresponding to FIG. 2, illustrating a torqueconverter according to a second embodiment of the invention,

FIG. 5 is a view corresponding to FIG. 2, illustrating a torqueconverter according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

A hydrokinetic torque coupling device according to a first embodiment ofthe invention is shown in FIGS. 2 and 3. The hydrokinetic torquecoupling device is more particularly a hydrodynamic torque converter.Such device makes it possible to transmit a torque from the output shaftof an internal combustion engine in a motor vehicle, such as forinstance a crankshaft 1, to a transmission input shaft 2. The axis ofthe torque converter bears reference X.

In the following, the words “axial” and “radial” are defined relative tothe X axis.

The torque converter conventionally comprises an impeller wheel 3, ableto hydrokinetically drive a turbine bladed wheel 4 through a reactor 5.

The impeller wheel 3 is fastened to a cover consisting of twobell-shaped parts 11 a, 11 b assembled together by welding and definingan internal volume 12 accommodating the impeller wheel 3, the turbinewheel 4 and the reactor 5. Said cover 11 a, 11B, also more generallyreferred to as cover 11, comprises fastening means 13 making it possibleto rotationally couple said cover 11 with the crankshaft 1.

The torque converter further comprises a central hub 8, the radiallyinternal periphery of which is ribbed, with an X axis and accommodatedin the internal volume 12 of the cover 11. The central hub 8 comprisesan annular rim 14 which radially extends outwards and a front end,facing the turbine wheel, which forms a radial surface 15.

The turbine wheel 4 is fastened to the first annular rim 14 of thecentral hub 8, for instance by rivets 16 or by welding.

Two radially internal annular flanges 17 are mounted in said internalvolume 12, with the two flanges 17 being fastened by their radiallyinternal periphery to the rim 14 of the hub 8 by rivets 16, as mentionedabove, or by welding, for instance.

The flanges 17 radially extend and comprise each a radially internalportion 17 a and a radially external portion 17 b. The radially internalportions 17 a of both flanges 17 are axially closer to each other thanthe radially external portions 17 b of both flanges.

Two radially external annular flanges 19, 20 are further mounted in theinternal volume 12 of the cover 11 around the internal flanges 17. Theexternal flanges 19, 20 are fastened together as will be described ingreater details hereunder,

The external flange 19 positioned behind or in the vicinity of theturbine wheel 4 is totally positioned radially outside the internalflanges 17. The external flange 20 positioned on the front, partiallyextends radially beyond the internal flanges 17 and partially extendsradially opposite said internal flanges 17. The external flange 20 morespecifically comprises a first radially internal part 20 a, and a secondradially external part 20 b fastened together by rivets, for instance.The second part 20 b of the flange 20 comprises a radial zone 20 c fixedto the first part 20 a and a cylindrical rim 20 d mounted about acylindrical part 8 a of the central hub 8 through a rolling bearing 18,such as a ball bearing, for instance. The cylindrical rim 20 d forexample surrounds the external ring of the rolling bearing 18.

Two supporting members or rolling bodies 21 shaped as rollers orcylindrical rollers, are fixed on the radially external periphery of theexternal flanges 19, 20. The rolling bodies 21 are positioned so as tobe diametrically opposed. The rolling bodies 21 are more specificallymounted about shafts 22 which axially extend between the two externalflanges, with said shafts being mounted on the external flanges 19, 20using bolts 23 or rivets, for instance. The rolling bodies 21 aremounted on the shafts 22 through rolling bearings 24, such as needlebearings, for instance.

The shafts 22 form spacers which make it possible to preserve thespacing between the external flanges 19, 20 with the latter beingfastened together at least by bolts 23 or matching rivets.

Two elastic leaves 25 are mounted between the internal and the externalflanges. As can be best seen in FIG. 3, each elastic blade 25 morespecifically comprises a fastening portion 25 a mounted between theradially external parts 17 b of both internal flanges 17 and fastened tothe latter by rivets 26, here three in number for each blade 25, and anelastic portion comprising a radially internal strand 25 b, a radiallyexternal strand 25 c, and a bowed or bent portion 25 d connecting theinternal strand 25 b and the external strand 25 c. The bowed or bentportion 25 d has an angle of approximately 180°. In other words, theelastically deformable portion of the elastic blade 25 comprises tworegions radially shifted relative to each other and separated by aradial space.

The external strand 25 c develops on the circumference with an angleranging from 120° to 180°. The radially external strand 25 c comprises aradially external surface 25 e which forms a raceway supported by thecorresponding rolling body 21, with said rolling body 21 beingpositioned radially outside the external strand 25 c of the elasticblade 25. The raceway 25 e has a globally convex shape. The raceway 25 emay directly consist of a zone of the external strand 25 c or of a partwhich is added onto said external strand 25 c.

Each external strand 25 c is adapted to axially rest on opposite radialsurfaces 31 of the external flanges 19, 20.

Between each elastic blade 25 and the matching rolling body 21, thetransmitted torque is broken down into radial stresses and peripheralstresses. Radial stresses make it possible for the matching blade 25 tobend and peripheral stresses make it possible for the matching rollingbody 21 to move on the raceway 25 e of the blade 25 and to transmit thetorque.

The torque converter further comprises clutch means 10 adapted torotationally couple the cover 11 and the external flanges 19, 20 in theengaged position, and adapted to release the cover 11 of the externalflanges 19, 20 in a disengaged position.

The clutch means 10 comprise an annular piston 27 which extends radiallyand is accommodated in the inner space 12 of the cover 11, the radiallyexternal periphery of which comprises a resting area equipped withclutch lining 28 and adapted to rest on the part 11 b of the cover 11 inan engaged position, so as to provide a rotational coupling of the cover11 and the piston 27.

A linking member 29 is fastened to the piston, for instance by rivets,in a zone positioned radially inside the clutch lining 28. The linkingmember 29 and the cover 11 may of course consist of one single part,without the operation of the torque converter being affected.

The linking member 29 comprises at least protruding zones 32 engaged inrecessed zones 33 of the flange 20. More particularly, the protrudingparts are lugs 32 formed by cutting and folding the linking member forinstance.

The piston 27 is thus rotationally coupled to the external flanges 19,20 while enabling the axial motion of the piston 27 relative to theflange 20 between the engaged and disengaged positions thereof. Themotion of the piston 27 is controlled by pressure chambers positioned oneither side of the piston 27. Besides, the motion of the piston 27 inthe disengaged position may be limited by the radially internalperiphery of the piston 27 resting on the radial surface 15 of thecentral hub 8.

It should be noted that, in this embodiment, the piston 27 can be somounted as to pivot directly about the transmission input shaft 2.

Such clutch means 10 make it possible to transmit a torque from thecrankshaft 1 to the transmission input shaft 2, in a determinedoperation phase, without any action by the hydrokinetic coupling meansconsisting of the impeller wheel 3, the turbine wheel 4 and the reactor5.

In operation, the torque from the crankshaft 1 is transmitted to thecover 11 through the fastening means 13. In the disengaged position ofthe piston 27, the torque goes through the hydrokinetic coupling means,i.e. the impeller wheel 3 and then the turbine wheel 4 fixed to theflange 8. The torque is then transmitted to the transmission input shaft2 coupled to the hub through the internal ribs of the hub 8.

In the engaged position of the piston 27, the torque from the cover 11is transmitted to the external flanges 19, 20, then to the internalflanges 17 through the damping means formed by the elastic leaves 25 andby the supporting members 21. The torque is then transmitted to theinternal hub 8 whereon the internal flanges 17 are fastened, then to thetransmission input shaft 2 coupled to the hub 8 through the internalribs of said hub 8.

In the engaged position of the piston 27, when the torque transmittedbetween the cover 11 and the hub 8 varies, the radial stresses exertedbetween each elastic blade 25 and the matching rolling body 21 vary andthe bending of the elastic blade 25 is modified. The modification in thebending of the blade 25 comes with a motion of the rolling body 21 alongthe matching raceway 25 e due to peripheral stresses.

The raceways 25 e have profiles so arranged that, when the transmittedtorque increases, the rolling bodies 21 each exert a bending stress onthe matching elastic blade 25 which causes the free distal end of theelastic blade 25 to move towards the X axis and a relative rotationbetween the cover 11 and the hub 8 such that the later move away fromtheir relative rest position. Rest position means the relative positionof the flange 11 relative to the hub 8, wherein no torque is transmittedbetween the latter.

The profiles of the raceways 25 e are thus such that the rolling bodies21 exert bending stresses having radial components and circumferentialcomponents onto the elastic leaves 25.

The elastic leaves 25 exert, onto the rolling bodies 21, a backmovingforce having a circumferential component which tends to rotate therolling bodies 21 in a reverse direction of rotation and thus to moveback the turbine wheel 4 and the hub 8 towards their relative restposition, and a radial component directed outwards which tends tomaintain the raceway 25 e supported by the matching rolling body 21.

When the flange 11 and the hub 8 are in their rest position, the elasticleaves 25 are preferably radially pre-stressed toward the X axis so asto exert a reaction force directed radially outwards, so as to maintainthe leaves 25 supported by the rolling bodies 21.

The profiles of the raceways 25 e may equally be so arranged that thecharacteristic transmission curve of the torque according to the angulardisplacement is symmetrical or not relative to the rest position.According to an advantageous embodiment, the angular displacement may bemore important in a so-called direct direction of rotation than in anopposite, so-called reverse direction of rotation.

The angular displacement of the cover 11 relative to the hub 8 may begreater than 20°, preferably greater than 40°.

The elastic leaves 25 are regularly distributed around the X axis andare symmetrical relative to the X axis so as to ensure the balance ofthe torque converter.

The torque converter may also comprise friction means so arranged as toexert a resisting torque between the flange 11 and the hub 8 during therelative displacement thereof so as to dissipate the energy stored inthe elastic leaves 25.

FIG. 4 shows a second embodiment of the invention, which is differentfrom the one shown in FIGS. 2 and 3 in that the second part 20 b of theflange 20 comprises a shoulder delimiting a cylindrical surface 34extending at its front end in a radial surface 35, with the rollingbearing 18 being accommodated in said shoulder and adapted to rest onthe radial surface 35 of said shoulder.

The central hub 8 further comprises a shoulder delimiting a cylindricalsurface 36 extending at its rear end in a radial surface 37, with therolling bearing 18 being accommodated in the shoulder of the central hub8 and being adapted to rest on the matching radial surface 37.

In this embodiment too, the piston 27 can be mounted around acylindrical part 38 of the central hub 8 formed at the front end of saidhub 8 for instance. The radial surface 15 supporting the piston 27 inthe disengaged position is formed behind the above-mentioned cylindricalpart.

FIG. 5 shows a third embodiment of the invention which is different fromthe one shown in FIGS. 2 and 3 in that the flange 20 is formed in onesingle part, the radially internal periphery of which comprises a rim 39surrounding the rolling bearing 18. Besides, in this embodiment, thepiston 27 can be mounted around a cylindrical part 38 of the central hub8 formed at the front end of said hub 8 for instance. The radial surface15 supporting the piston 27 in the disengaged position is formed behindthe above-mentioned cylindrical part 38.

The invention claimed is:
 1. A hydrokinetic torque coupling device for amotor vehicle comprising a torque input element (11) intended to becoupled to a crankshaft (1); a turbine wheel (4), an impeller wheel (3)rotationally coupled to the torque input element (11) and able tohydrokinetically drive the turbine wheel (4), a torque output element(8) intended to be coupled to a transmission input shaft (2); dampingmeans (21, 25), clutch means (10) adapted to rotationally couple thetorque input element (11) and the torque output element (8) in anengaged position, through the damping means (21, 25), and able torotationally uncouple the torque input element (11) and the torqueoutput element (8) in a disengaged position, with the damping means (21,25) being adapted to act against the rotation of the torque inputelement (11) relative to the torque output element (8), in the engagedposition of the clutch means (10); and, the damping means (21, 25)comprising at least an elastic blade (25) which rotates together withthe torque output element (8), and a supporting member (21) carried bythe clutch means (10), with the blade (25) being elastically maintainedagainst said supporting member (21), with said elastic blade (25) beingadapted to bend upon rotation of the torque input element (11) relativeto the torque output element (8), in an engaged position, with thesupporting member (21) being mounted on at least one supporting flange(20) and so mounted as to pivot on the torque output element (8) througha bearing (18).
 2. A hydrokinetic torque coupling device according toclaim 1, wherein the supporting flange (20) comprises a radiallyinternal part (20 b) mounted about the torque output element (8) throughthe bearing (18), and a radially external part (20 a) whereon thesupporting member (21) is mounted, with the radially internal andexternal parts (20 b, 20 a) being fastened together.
 3. A hydrokinetictorque coupling device according to claim 2, wherein the radiallyinternal part (20 b) of the supporting flange (20) comprises acylindrical rim (20 d) surrounding the bearing (18).
 4. A hydrokinetictorque coupling device according to claim 2, wherein the radiallyinternal part (20 b) of the supporting flange (20) comprises a shoulderdelimiting a cylindrical surface (34) extending at one end into a radialsurface (35), with the bearing (18) being accommodated in said shoulderand adapted to rest on the radial surface (35) of said shoulder.
 5. Ahydrokinetic torque coupling device according to claim 1, wherein itcomprises: at least one internal flange (17) which rotates together withthe torque output element (8); and, at least one radially externalflange (19, 20) positioned radially partially outside the internalflange, and pivoting relative to the internal flange (17), with theelastic blade (25) rotating together with the internal flange (17), andthe external flange (19, 20), rotating with and being connected to thesupporting member (21).
 6. A hydrokinetic torque coupling deviceaccording to claim 1, wherein it comprises: two radially internalflanges (17) rotating together with the torque output element (8); and,two radially external flanges (19, 20) mounted so as to pivot about saidinternal flanges (17), with the elastic blade (25) being mounted in aspace axially arranged between the internal flanges (17) and between theexternal flanges (19, 20), with the supporting member (21) being mountedin a space axially arranged between the external flanges (19, 20), withone of the external flanges (19, 20) being formed by the supportingflange (20).
 7. A hydrokinetic torque coupling device according to claim1, wherein the turbine wheel (4) is rotationally coupled to the torqueoutput element (8) and to the internal flange (17).
 8. A hydrokinetictorque coupling device according to claim 1, wherein the clutch means(10) comprise at least one piston (27) rotationally coupled to thesupporting flange (20), with the piston (27) being able to move betweenan engaged position wherein it is rotationally coupled to the torqueinput element (11) and a disengaged position wherein it is rotationallyuncoupled from the torque input element (11).
 9. A hydrokinetic torquecoupling device according to claim 8, wherein the torque output element(8) comprises a radial surface (15), with the motion of the piston (27)in the engaged position being limited by the piston (27) resting on saidradial surface (15) of the torque output element (8).
 10. A hydrokinetictorque coupling device according to claim 1, wherein the torque outputelement comprises a central hub (8).
 11. A hydrokinetic torque couplingdevice according to claim 1, wherein the bearing is a rolling bearing(18).
 12. A hydrokinetic torque coupling device according to claim 1,wherein the bearing is a ring.
 13. A hydrokinetic torque coupling deviceaccording to claim 1, wherein it comprises a reactor (5), with theimpeller wheel (3) being able to hydrokinetically drive the turbinewheel (4) through the reactor (5).
 14. A hydrokinetic torque couplingdevice according to claim 2, wherein it comprises: at least one internalflange (17) which rotates together with the torque output element (8);and, at least one radially external flange (19, 20) positioned radiallypartially outside the internal flange, and pivoting relative to theinternal flange (17), with the elastic blade (25) rotating together withthe internal flange (17), and the external flange (19, 20), rotatingwith and being connected to the supporting member (21).
 15. Ahydrokinetic torque coupling device according to claim 3, wherein itcomprises: at least one internal flange (17) which rotates together withthe torque output element (8); and, at least one radially externalflange (19, 20) positioned radially partially outside the internalflange, and pivoting relative to the internal flange (17), with theelastic blade (25) rotating together with the internal flange (17), andthe external flange (19, 20), rotating with and being connected to thesupporting member (21).
 16. A hydrokinetic torque coupling deviceaccording to claim 4, wherein it comprises: at least one internal flange(17) which rotates together with the torque output element (8); and, atleast one radially external flange (19, 20) positioned radiallypartially outside the internal flange, and pivoting relative to theinternal flange (17), with the elastic blade (25) rotating together withthe internal flange (17), and the external flange (19, 20), rotatingwith and being connected to the supporting member (21).
 17. Ahydrokinetic torque coupling device according to claim 2, wherein itcomprises: two radially internal flanges (17) rotating together with thetorque output element (8); and, two radially external flanges (19, 20)mounted so as to pivot about said internal flanges (17), with theelastic blade (25) being mounted in a space axially arranged between theinternal flanges (17) and between the external flanges (19, 20), withthe supporting member (21) being mounted in a space axially arrangedbetween the external flanges (19, 20), with one of the external flanges(19, 20) being formed by the supporting flange (20).
 18. A hydrokinetictorque coupling device according to claim 3, wherein it comprises: tworadially internal flanges (17) rotating together with the torque outputelement (8); and, two radially external flanges (19, 20) mounted so asto pivot about said internal flanges (17), with the elastic blade (25)being mounted in a space axially arranged between the internal flanges(17) and between the external flanges (19, 20), with the supportingmember (21) being mounted in a space axially arranged between theexternal flanges (19, 20), with one of the external flanges (19, 20)being formed by the supporting flange (20).
 19. A hydrokinetic torquecoupling device according to claim 4, wherein it comprises: two radiallyinternal flanges (17) rotating together with the torque output element(8); and, two radially external flanges (19, 20) mounted so as to pivotabout said internal flanges (17), with the elastic blade (25) beingmounted in a space axially arranged between the internal flanges (17)and between the external flanges (19, 20), with the supporting member(21) being mounted in a space axially arranged between the externalflanges (19, 20), with one of the external flanges (19, 20) being formedby the supporting flange (20).
 20. A hydrokinetic torque coupling deviceaccording to claim 5, wherein it comprises: two radially internalflanges (17) rotating together with the torque output element (8); and,two radially external flanges (19, 20) mounted so as to pivot about saidinternal flanges (17), with the elastic blade (25) being mounted in aspace axially arranged between the internal flanges (17) and between theexternal flanges (19, 20), with the supporting member (21) being mountedin a space axially arranged between the external flanges (19, 20), withone of the external flanges (19, 20) being formed by the supportingflange (20).